Automatic slack adjuster



Oct. 19, 1937. E. c. MOODY 2,096,463

AUTOMATIC SLACK ADJUSTER Filed June 13, 1956 2 Sheets-Sheetl lNvENToR EDWIN C. MOODY.

ATTORNEY Oct. 19, 1937. E. c. MOODY 2,096,463

AUTOMATIC sLAcK ADJUSTER Filed June 13, 1936 2 Sheets-Sheet 2 m uw INVENTOR EDWIN C. MOGDY. A

BY @amg ATTORNEY Patented oef. 19, 1937 PATENT OFFICE n 2,096,463 AUTOMATIC SLACK ADJUSTER Edwin C. Moody, Wilmerding, Pa., assignor to i The Westinghouse Air Brake Company, Wilmerding, Pa., a corporation of Pennsylvania Application June 13, 1936, Serial No. 85,007 V15 claims. (o1. lesa-203) This invention relates to automatic slack adjusters for railway vehicle brakes and more particularly to that type of slack adjusterr in vwhich the slack take-up means and the 'motor for actuating the slack take-up means are coaxially arranged. f 4

The principal object of the invention is to provide an improved slack adjuster of ther above mentioned type. n f

Otherobjects and advantages will appear in the following more detailed description of the invention. g l j In the accompanying drawings', Fig. l is a longitudinal vertical sectional View of an automatic f slack adjusterconstructed in accordance with the invention; Fig. 2 is a' fragmentary horizontal sectional View of the same taken on the line 2-2 of Fig. 1 and Fig. 3 is a cross-sectional view taken on the line 3-3 of Fig. 2. Fig. 4 is a longitudinal sectional View of another form of automatic slack adjuster constructed in accordance with the invention and Fig. 5 is a cross-sectional View of the same taken on the line 5 5 of Fig. 4. Figs. 6 and 7 are fragmentary vertical and horizontal sectional views of still another form of slack adjuster constructed in accordance with the invention.'

- As shown in Figs. 1,y 2 and 3 of the drawings, the automatic slack adjuster may comprise a slack '3o take-up cylinder I which, at one end, has an integral pressure head 2 and which, at the other end, has secured thereto a non-pressure head 3. v The casing also comprises a hollow guide por- Vtion 4 which extends outwardly from the pressure head 2. Theouter end of this guideportion Avris inthe form of an integral vertically disposed Y`securingfilange 5 which may be secured to any suitable supporting member ofa car body or car truck or may be secured to the brake cylinder of a fluid pressure brake equipment. Contained in the guide Yportion and slidably guided thereby is Va cross-,head 6 which issecured to the outer end roi a non-rotatable adjusting member or screw l. rThe cross-head 6 is operatively connected, by

v means of a pin 8, to a member 9 to be adjusted,

is annular in form and which surrounds and slidably contacts With the inner wall, which piston has secured to its pressure face an annular packing I2 having an inner annular skirt I3 which slidably engages the outer surface of the 5 inner cylinder wall and also having an outer annular skirt I4 which slidably engages the inner surface of the outer cylinder wall.

The piston I I is provided with an annular sleeve I5 which slidably contacts the inner surface of 10 the outer wall of the cylinder. The sleeve I5 is provided with a narrow longitudinally extending exterior groove I6 for the reception of the inner end of a bolt I'I extending through and having screw-threaded connection with the outer wall 15 of the cylinder I. As shown in Fig. 3 this bolt prevents rotation of the piston relative to the cylinder and as shown in Fig. 1 serves as a stop for limiting movement in the direction toward the pressure head 2 so as to prevent the packing I2 20 from engaging and being damaged by the pressure head.

The inner end portion of the adjusting or slack take-up member 'I extends through a central opening in the pressure head 2 and an aligned 25 `opening in a bearing member I8 which is preferably integral with the inner annular wall of the cylinder. Beyond the member I8 the end of the adjusting member 'I has screw-threaded connection with rotatable slack take-up nut I9 which is 30 journalled in an annular sleeve 20 which is integral with the non-pressure head 3, which sleeve also serves as a thrust bearing for preventing longitudinal movement of the nut in a direction toward the right hand. Longitudinal movement 35 of the nut in the opposite direction is prevented by the engagement of the inner end of the nut with a thrust bearing plate 2l which abuts the bearing member I8.

The slack take-up nut I9 is provided with a 40 circular clutch member 22 which is located within the cylinder I adjacent the inner end of the sleeve 20 ofthe non-pressure head 3 and which is provided with an inwardly directed annular ange having formed on its face ratchet clutch teeth 23. 45 These teeth, as will hereinafter more fully appear, are adapted to be engaged by similar clutch teeth 24 formed on the end of the annular sleeve 25 of a clutch member 26 contained in the cylinder I. The sleeve 25 is concentric with the cylinder I 50 and extends longitudinally thereof into telescopic relation with the annular sleeve I5 of the piston II. There is a slight operating clearance provided between the inner surface of the piston v.Sierre l5 and the clutch sleeve 25 to permit relav55 tive longitudinal movement between the sleeves and to permit rotary movement of the sleeve relative to the piston sleeve I5. Integral with the telescoped end of the sleeve 25 is an annular spring seat 2 and interposed between and operatively engaging this spring seat and the inner face of the piston is a helical spring 29.

The inner edge of the spring seat 2l slidlably engages the inner wall i@ of the cylinder I so that said wall serves to guide the clutch member 26'as it rotates and moves longitudinally of the cylinder. It will be understood from the foregoing description that the piston also serves to guide X,this clutch member.

Rigidly secured to the piston I I and extending outwardly from the non-pressureface thereof are longitudinally disposed bolts 29 which pass through accommodating arcuate openings 30 provided in the spring seat 2'I of the clutch `mem.- ber 2B, the width of the openings being slightly Igreater than the diameter of the bolts to insure free longitudinal movement of the bolts relative to the clutch member. The free ends of the bolts are provided with heads 3| which are adapted to'engage the inner surface of the spring seat 2'I to move the clutch member 26 longitudinally in a direction toward the left hand as will hereinafter more fully appear and to maintain this clutch member out of engagement with the clutch member 22 of the slack take-up nut I9 as shown in Fig. 2.

The piston sleeve I5 adjacent its end has secured to its inner face, by means of screw threads, radially arranged inwardly extending laterally disposed headed shoulder bolts 32 which pass through longitudinally extending spiral slots 33 in the sleeve 25 o'f the clutch member 26, rollers 34 being mounted on the bolts for driving engagement with the edges of the slots.

Interposed V'between and operatively engaging the end of the piston sleeve I5 and an inner surface of the non-pressure head 3 is a heavy Voperatinghelical spring 35 which normally maintains vthe piston `II in the position in which `itis shown in Fig. 1.

The right hand end of the slack take-up nut I9 as shown is in the form* of kan annularsleeve 31 and extends beyond the outer surface of the non-pressure head 3. Surrounding and contacting the sleeve 31 and mounted in a recess formed in the outer face of the non-pressure head is a felt washer 38 which is clamped in place by an annular washer 39 secured to the non-pressure head by means of counter-sunk machine screws. This felt washer permits air to flow, by way of the necessary clearance Aspace between the nut and the Vbearing sleeve 20 of the nonpressure head, to and from the chamber at the non-pressure side of the piston, and is adapted to cleanse the Ainlowing air of dirt and moisture.

Mounted in the pressure head 2 of the cylinder and surrounding and contacting the adjusting screw member I is a Vpacking gland` 49 which is adapted to prevent the entrance of air from the atmosphere to the chamber at the non-pressure side of the piston by way of the clearance space between the member 'I and the pressure head 2.

At the pressure side of the piston I I is a chamber 4I which is connected to a pipe 42 through which fluid under pressure is adapted to be supplied to and released from the piston chamber 4 I The -pipe 42 is connected in the usual manner to the brake cylinder of a iiuid pressure brake equipment, so that when the brakes are released the piston chamber 4I is vented to the atmosphere by way of the non-pressure chamber of the brake cylinder and when an application of the brakes is being effected and the brake cylinder piston moves far enough to uncover the pipe 42 to the brake cylinder piston chamber, iluid under pressure for actuating the slack take-up piston IIV flows to the piston chamber 4I. This control of the supply and release of fluid under pressure to and from the slack take-up cylinder is so well known that rit is deemed unnecessary to illustrate the brake cylinder or any other part of the fluid pressure brake equipment.

In operation when the brake shoes or other parts 4of the brake rigging become worn to such an extent that, in veffecting an application of the brakes, the brake'cylinder piston, not shown, moves outwardly a sufficient distance to uncover the pipe 42, fluid under pressure flows from the .brake cylinder piston chamber through pipe 42V to the piston chamber 4I of the slack adjuster causing the piston II and thereby the piston sleeve I5 and bolts 29 to move outwardly in the direction toward the right hand, compressing the operating spring 35.

As the piston II begins to move under the influence of fluid pressure in chamber 4 I, the spring 28 acts tomove the clutch member 26 forwardly with the piston causing the teeth24 of the member to contact the teeth 23 of the clutch member 22 and by reason of such contact the'forward movement of the clutch member 26 is stopped.

Now as the forward movement of piston II continues the heads 3l of the bolts 29 are moved out of engagement with the spring seat 2I ofthe clutch member 25 and the forwardly moving rollers 34 acting on the clutch sleeve 25 within the slots 33 cause the clutch member to be rotated a short distance in a counter-clockwise direction relative to the piston sleeve I5 and clutch member 22 `in Viewing the apparatus from the vright hand end of Fig. 2, the teeth 24 of the member 26 ratcheting over the teeth 23 of the member 22. It will here be understood that when this rotary movement of the clutch member 26 occurs the brakes are applied so that the adjusting screw is subjected to a comparatively heavy force which increases the resistance of the nut to rochamber, the brake cylinder. piston is causedA to move toits normal release position inthe usual well known manner, the piston in its traverse first cutting Voff communication between the pipe 42 and the brake cylinder piston chamber and then establishing communication from the pipe 42 to the atmosphere by way of the non-pressure chamber of the brake cylinder, so that fluid under pressure is vented from the slack take-up piston chamber 4I.

Withthe piston chamber 4I thus vented, lthe compressed spring 35 acts to return the piston I i and thereby the piston sleeve I5, bolts 29, shoulder bolts 32 and rollers 34 to their normal position as shown in Figs. l and 2, and during their return movement are prevented from rotating by the engagement of the piston sleeve by the bolt I'I. Since the piston sleeve and bolts 32 cannot rotate, the 'rollers acting in the slots ,3 3 on the lclutch sleeve 25 cause the clutch member 26 to Vrotate in a clockwise vdirection in viewing the apparatus from the right hand end of Fig. Y2.

rWhen the clutch member is rotated in this direction, the teeth 24 engage the teeth 23 of the clutch member 22, so'that the member 26 imparts rotary movement to the clutch member 22 and consequently to the nut I 9, causing the adjusting member 1 to be moved in a direction toward the right hand and 'thereby effecting the take up of slack in the brake rigging.

s Itwill here be understood that during the `major portion of lthe adjusting stroke of the piston Il, the spring 28, which'has'been kcompressed by the piston, acts to maintain theclutch member 26 in driving engagement with the clutch member 22. However, as the piston is nearing the completion of its adjusting stroke, the heads Vof the bolts 29 engage the spring seat 21 of the clutch member 26 and as the piston completes its stroke the bolts move the clutch member 26. out of driving engagement with the clutch member 22 as shown in Figs. 1 and 2.

When Worn brake shoes are to be replaced by ynew ones, it is necessary to move the cross-head 6 and adjusting member 'l in a direction toward the left'hand to increase the slack in the rigging sui'iciently to compensate for the greater thickness of the new shoes, and in order to dofthis the nut 'I9 is turned` manually in a counterclockwise rdirection by means of a wrench or other suitable tool which may be applied to the sleeve portion 3'! of the nut. If it should be desired to manually operate the slack adjusted to take up slack the nut I9 is turned in a clockwise direction. It will be noted that since the clutch members 22 and 26 are normally out of engagement with each f other an operator may adjust the brakes by the single manual operation of turning the nut I9 as just described.

The automatic slack adjuster illustrated in Figs. 4 and 5 has substantially the same operating Y lcharacteristics as the adjuster just described but whichy Will now be pointed out.

there are several. differences in the construction In this adjuster the cylinder 50 yand piston 5| mounted therein are of circular form instead of annularr and the pressure head of the cylinder is in theform of a ilange'52 whereby the adjuster is ladapted to be Secured to any desired supporting structure. The cross-head 6 is slidably guided by spaced longitudinally extending guide'members 53 which are integral with the non-pressurehead .s4 of the, cylinder instead ory being integral with the pressure head. Securedto the outer ends of they guide members 53 is a connecting member 55 which is provided with an vopening 56 through which theV outer end of a rotatable slack takeup screw 5'! extends, the outer end of the screw having welded or otherwise secured thereto a rcollar 58 which is adapted to be engaged by a wrench orV other suitable tool for tating the screw. l

The inner end of the slack take-up screw is secured to clutch member 22 so as to rotate theremanually rovwith and between its ends has screw-threaded connection with the cross-head 5.

59 with an outer surface of the non-pressure head,

which collar is removably secured to the clutch member by means of a pin 60.

Aside from the differences above noted the slack adjuster is substantially the same as shown in Figs. 1, 2 and 3.

The operation of this slack adjuster is substantially the same as that of the adjuster illustrated in Figs. 1, 2 and 3 except that the clutch member 22 rotates the adjusting screw instead of an adjustingnut and that the screw is not movable longitudinally.

In Figs. 6 and 7 a modification is illustrated in which the bolts 29 are omitted and in which the shoulder bolts 32 act to move the clutch member 26 out of driving engagement with the clutch member 22 when the take-up piston nears the limit of its adjusting stroke. This construction may be employed in either of the slack adjusters shown.`

While three illustrative embodiments of the invention have been described in detail, it is not my intention to limit its scope to these embodiments or otherwise than by the terms of the appended claims.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is:

1.'In an automatic slack adjuster for railway brake rigging, in combination, a member rotatableto take up slack, rotatable means axially aligned with the member operative to actuate the member, a piston operative to actuate said means, and means carried by said piston operative as the piston nears the limit of its adjusting stroke for moving said means out of operative relation to said member.

2. In an automatic slack adjuster for railway brake rigging, in combination, a member rotatable to take up slack, rotatable means in axial alignment with the member operative to actuate the member, a piston operative to actuate said means, a resilient member for maintaining said means in operative engagement with said member as said means is being operated, and means carried by said piston and operated thereby for moving said means out of operative engagement with said member as the piston'nears the limit of its adjusting stroke.

3. In an automatic slack adjuster for railway brake rigging, in combination, a member rotat- .f

able to take up slack, means operative to actuate said member, a piston operative to actuate said means, a resilient member interposed between andoperatively engaging said piston and means for holding said means in operative engagement with said member when the piston is operated to actuatethe means, and means carried by said piston and operated thereby for moving said means out of operative engagement with said member against the opposing action of said resilient member as the piston nears the limit of its adjusting stroke.

4. Inan automatic slack adjuster for railway brake rigging, in combination, a slack take-up element rotatable to take up slack, a piston, means for preventing rotary movement of said piston, a member rotatably carried by said piston and operative thereby for actuating said element, and means carried by said piston adapted to move said member out of operative engagement with said element as the piston nears the limit of its adjusting stroke.

5. In an automatic slack adjuster for railway brake rigging, in combination, a slack take-up element rotatable to take up slack, a piston',

means or preventing rotary movement of` said piston, a member rotatably carried by said'piston and operative thereby for actuating said element, means interposed between and operatively engaging said piston and member adapted to maintain said member in operative engagement With ksaid element when the piston is operated to actuate said member, and means carried by said piston adapted to move said member out of engagement with said yelement as the piston nears thelimit of its adjusting stroke.

6. In an vautomatic slack adjuster for railway brake rigging, in combination, a slack take-up element rotatable to take up slack', a piston, means for preventing rotary movement oi said piston, a member rotatably carried by said piston rand operative to actuate said element, means carried by said piston and operative thereby for imparting rotary movement to said member and thereby to said element, and means carried by said piston adapted to move said member out of `operative engagement with said element as the piston approaches the end of its adjusting stroke. 7. In an automatic slack adjuster for railway brake rigging, in combination, a slack-take-up element rotatable to take up slack, clutch means comprising a pair oi rotatable clutch members for actuating said element, said clutch members being normally out oi operative engagement with each other, a piston for actuating said clutch means,fs`aid piston having a conditioning stroke formoving one of said clutch members into operative engagement with the other and to condition the clutch means for taking up slack and having anadjusting stroke for actuating said clutchmeans to take up slack, and means cooperating with said piston and clutch means for effecting the separation of said clutch members as the piston nears the limit of its adjusting stroke.

8. In an automatic slack adjuster for railway brake rigging, in combination, a slack take-up element rotatable to take up slack, clutch means comprising a pair of rotatable clutch members for actuating said element, said clutch members being normally out of operative engagement with each other, a piston for actuating said clutch means, said piston having a conditioning stroke for moving one of said clutch members into operative engagement with the other and to condition the clutch means for taking up slack and having an adjusting stroke for actuating said clutch means to take up slack, yieldable means interposed between and operatively engaging the first mentioned clutch member and said piston and operative to maintain the clutch member in engagement with said other clutch member when the piston is being operated to actuate said clutch means, and means carried by said piston adapted to move the first mentioned clutch member out of engagement with said other clutch member as the piston nears the end of its adjusting stroke.

9. In an automatic slack adjuster for railway brake rigging, in combination, a casing comprising a cylinder, an element rotatably jcurnalled in said casing for taking up slack, a pair of axially aligned interengaging clutch members contained in said cylinder operative to actuate said element, a piston in said cylinder operative for actuating said clutch members and thereby said element to take up slack, and means carried by said piston adapted to disengage said clutch members when the piston nears the end of its adjusting stroke.

10. In an automatic slack adjuster for railway brake rigging, in combination, a casing comprising a cylinder, an element rotatably jcurnalled in said casing for Vtaking up slack, a pair of axially aligned clutch members containedV in said cylinder for actuating said element, said clutch members being normally out of operative engagement with each other, a piston movable in one direction for moving one of said clutch members into contact with the other clutch member and for rotating the rst mentioned clutch member in one direction,ratchet means for preventing such rotary movement from being transmitted to said other clutch member and for transmitting rotary movement to said other clutch member when the first mentioned clutch. member is rotated in theV opposite direction, said piston being movable in another direction for rotating the rst mentioned clutch member in said opposite direction, and means operative as the piston nears the end of its travel in said other direction for moving the rst mentioned clutch member out of operative engagement with said other clutch member.

l1. In an automatic slack adjuster for railway brake rigging, in combination, a casing comprising a cylinder, an element rotatably Yjcurnalled in said casing for taking up slack, a pair of axially aligned clutch members contained in said cylinder for actuating said element, said` clutch members being normally out of operative engagement with each other, a piston movable in one direction for moving one of said clutch members intoV contact kwith the other clutch member and'for rotating the rst mentioned clutch member in one direction, ratchet means for preventing such rotary movement from being transmitted to said other clutch member and for transmitting rotary movement to said other clutch member when the rst mentioned clutch member is rotated in the opposite direction, said piston being movable in another direction for rotating the first mentioned clutch member in said opposite direction, and resilient means for maintaining the rst mentioned clutch member Vin engagement with said other clutch member as the first mentioned clutch member is being Arotated in said opposite direction.

12. In an automatic slack adjuster for railway brake rigging, in combination, a casing comprising a cylinder, an element rotatably jcurnalled inV said casing for taking up slack, a pair of axially aligned rotatable clutch members contained in said cylinder for actuating said element, said clutch members being normally out of operative engagement with each other, a piston movable in one direction for moving 'one of said clutch members into contact with the other clutch member and for rotatingv the iirst mentioned clutch member in one direction, ratchet means for preventing such rotary movement from being transmitted to said other clutch member and for trans-v mitting rotary movement to said other clutch member when the rst mentioned clutch member is rotated in the opposite direction, said piston being movable in another direction for rotating the rst mentioned clutch member in said opposite direction, resilient means for maintainingV ing a cylinder, an element rotatably mounted in rsaid casing for taking up slack, a piston operativelymounted in said cylinder, a member rotatably mounted in said piston adapted to be operated by said piston tovactuate said element,

said member being normally out of operative engagement with said element, means for moving said member into contact with said element upon 'movement of the piston in one direction, driving ment in'said opposite direction to said memberr andthereby to said element upon movement of the piston in another direction. 14. In an automatic slack adjusterfor railway brake rigging, in combination, a casing compris- Y q ing a cylinder, an element rotatably mounted in said casing for taking up slack, a piston operatively 'mounted in said cylinder, a member roy Vtatably mounted in said piston adapted to be operated by said piston to actuate said element,

Vsaid member being normally out of operative engagementrwith said element, resilient means interposed between and engaging said piston and member for moving said member into contact with said element upon movement of the piston in one direction, driving means carried by said piston and cooperating with said member to impart rotary movement to the member upon move- `ment of the piston in said direction, and ratchet means for preventing such rotary movement from being transmitted to said element, said ratchet means being operative for transmitting rotary movement from the member to the element upon rotation of the member in the opposite direction, said driving means on saidpiston being adapted to impart rotary movement in said opposite direction to said member and thereby to said element upon movement of the piston in the opposite direction.

15. In an automatic slack adjuster for railway brake rigging, in combination, a casing comprising a cylinder, an element rotatably mounted in said casing for taking up slack, a piston operatively mounted in said cylinder, a member rotatablyk mounted in said piston adapted to be operated by said piston to actuate said element, said member being normally out of operative engagement with said element, resilient means interposed between and engaging said piston and member for moving said member into contact with said element upon movement of the piston in one direction, driving means carried by said piston and cooperating with said member to impart rotary movement to the member upon movement of the piston in said direction ratchet vmeans for preventing such rotary movement from vmentupon movement of the piston in the opposite direction, and means carried by said piston for moving said member out of operative engagement with said element when the piston nears the end of its stroke in said other direction.

EDWIN C. MOODY. 

